Interview Question

difference between abstract and interface
How to save transient data
why externalisation when serializable exists
Internal implementation of hash map and hashset
Normalisation why it is required
explain 1st 2nd 3rd normal form
How to get thread result back - through callable interface
are serialised and deserialised object are the same object instances ?
Read about serialisation in one file and in multiple files and see the heap space .
Answer is No if heap spaces are different.
How to validate JSON
What is difference between merge and inverse
Object state in hibernate
would there be several instances of singleton class in different JVM
// yes different JVM have different class loader hence different objects would get instantiated.
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when to use second level cache in Hibernate 
Why criteria API are used ? - For dynamic invocation of query parameters. 
What are projections ? aggregate funcations
What are restrictions? where conditions 
QBE ? by passing dummy object in criteria
One To Many // give an example
Many To one // give an example
Hibernate Validator pattern 

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ThreadLocal usage


http://examples.javacodegeeks.com/enterprise-java/rest/jersey/jax-rs-queryparam-example/